Needles have a wide variety of applications in the medical field. For instance, needles are used to delivery therapeutic agents, collect bodily fluids, and fill drug delivery ports. In many such applications, there is a desire to avoid or reduce damage to the site in which the needle is inserted. For example, drug delivery ports such as intravascular drug access devices often include a chamber for holding a therapeutic agent and a pierceable rubber septum for receipt of a needle to either fill or empty the chamber. Repeated piercing of the septum with the needle can damage the septum leading to infusion of the septum fragments into the patient's vascular system or into any catheter or other device having access to the port, thereby occluding the port.
With respect to delivering a therapeutic agent to a target site in the body, particularly directly delivering a therapeutic agent to a target site, current injection needles have beveled open ends with Lancet point tips. Such open-ended needles have the potential to core tissue as the needles penetrate the tissue. In the case of directly delivering a therapeutic agent to a myocardial wall of the heart, since most myocardial direct injection procedures involve injecting a therapeutic agent into the left ventricle walls, the risk of tissue embolism into the left ventricular cavity exists.
Needle tips, such as the “pencil-point” needle and the “Huber” needle have been developed that attempt to reduce coring by the needle. A Huber needle has a distal portion with a lateral bend and a laterally facing opening. The needle terminates in a sharpened closed tip. A pencil-point needle has a lateral opening and a closed tip at the distal end. Because there are no distal openings in these types of needles, any therapeutic agent that passes through the lumens of these needles exits these laterally facing openings, which will direct the therapeutic agent in a radial direction. Such radial delivery may result in the therapeutic agent being ejected or squeezed back through its point of entry in the target site. This problem is exacerbated in situations where the therapeutic agent is injected into an actively contracting tissue such as the myocardium of the heart. In such a case, the therapeutic agent may be ejected or squeezed out through its point of entry by the repeated expansion and contraction of the heart muscle. This unintended and unwanted leakage can result in an unascertainable dosage of the therapeutic being ultimately received by the target site and arbitrary and unwanted interaction between leaked therapeutic agent and neighboring tissue and muscle.
Accordingly, there is a need for a needle that will prevent or minimize damage to the site in which the needle is inserted and that will direct the delivery of a therapeutic agent, or any infusion material, in a distal direction out of the needle.